Aerosol generator and lubricator and method of generating micronic size aerosol



Dec. 27, 1960 J. A. WILSON, JR. ETAL 2,966,312 AEROSOL GENERATOR ANDLUBRICATOR AND METHOD OF GENERATING MICRONIC SIZE AEROSOL Filed March 6,1958 2 Sheets-Sheet 1 INVENTOR. JESSE A. WILSON, JR. MORLEY V. FR/EDELLATTORNEY Dec. 27, 1960 J A WILSON, JR ETAL 2,966,312

AEROSOL. GENERATOR AND LU'ERICATOR AND METHOD OF GENERATING MICRONICSIZE AEROSOL Filed March 6, 1958 2 Sheets-Sheet 2 I E I i! run: I WW HMIn N h N A NN "W N HIEHH I INVENTOR.

JESSE A. WILSON JR. MORLEY v FR/EDELL ATTORNEY United States PatentQAEROSOL GENERATOR AND LUBRICATOR AND F GENERATING MICRONIC SIZE Jesse A.Wilson, J12, Littleton, and Morley V. Friedell, Wheat Ridge, Colo.,assignors to C. A. Norgren Co., Englewood, Colo., a corporation ofColorado Filed Mar. 6, 1958, Ser. No. 719,608

8 Claims. (Cl. 239-338) Our invention is directed to an apparatus forand a method of directly creating and generating a micronic size aerosolof lubricant in air without the use of settling chambers or the like andin particular to an aerosol generator for discharging into a compressedair line an aerosol of finely divided micronic sized particles of liquidlubricant in air wherein for all practical purposes all the liquid as itis discharged into the air stream is broken up into micronic sizedparticles.

As is well known, air line lubricators are for the purpose ofdischarging a fog of oil into an air stream for lubricating bearings,compressed air tools and various pneumatically operated devices and thegenerator of this invention, as will be explained, is to be incorporatedas an element of the lubricator for creating such an aerosol. However,in actuality, to utilize the aerosol generator of this invention it isonly necessary to supply compressed air or gas under pressure to the jetinlet of the generator, to supply liquid lubricant to the generatortubes formed integrally as a part thereof and to provide some sort ofmeans for conveying the resulting aerosol to the point of usage. Bearingthis in mind, it has been found desirable for the purpose ofillustration and not limitation to discuss and show the teachings ofthis invention by in corporating the generator in the compressed airpassage of a typical lubricator that includes the usual bowl for theliquid lubricant. Also hereinafter reference will be made to compressedair, air line, air under pressure, but it is to be understood thatvarious gaseous mediums could well be substituted for the air underpressure and thus the invention is not to be limited by use of thequoted phraseology.

For the purpose of high lighting the advantages of this invention,perhaps at the outset a brief rsum of the conventional types or classesof air line lubricators should be provided. The first conventional typeof lubricator known as the Mist or Fog lubricator, and hereinafterreferred to as type A, really involves injecting a spray of lubricantinto an air line through which compressed air flows and this willproduce an aerosol of air and oil fog with the latter being composed offine and coarse particles of lubricant. Contrary to the other type oflubricator which will be described hereinafter, type A does notcontaminate or cause undesirable eifects in the main lubricant supplybut it does create a relatively coarse fog in which at least 95 percentof the mist would be in particle sizes larger than two microns, with themajor portion thereof being at least fifty microns in size. This heavymist has a definite tendency to settle out in the flow lines, thus ineffect delivering a large portion of the liquid in droplet or solid formand, of course, such is totally unsatisfactory in applications where afinely divided aerosol of micronic sized particles is required, such asfor lubricating certain bearings, some air-driven devices, etc. On theother hand, type A of lubricator, as well as the other type to bediscussed, has many advantages and commercial applications as evidencedby Cata- 2,966,312 Patented Dec. 27, 1960 log 800 of the C. A. NorgrenCo. of Englewood, Colorado.

The other type of conventional lubricator, hereinafter referred to astype B, does provide an aerosol of micronic sized particles, but asillustrated in several United States patents, a few of which arehereinafter identified, a good part of the oil that is initially fed toand intermingled with the air stream following atomization is directedagainst a baflle or the like and then discharged into a settling spaceor chamber whereby the large oil particles are returned to the lubricantreservoir and the fine, light or micronic sized particles are carried bythe air stream to the point of usage. In other words, the micronic sizedparticles, never more than about 5 percent of the total liquid initiallysprayed or atomized, pass through the outlet of the lubricator to thepoint of usage while the remainder of the liquid comprising the heavierparticles rejoin the main liquid supply and are recirculated over andover again through the same cycle. Thus, when using compressed air forinstance, the liquid lubricant would be aerated an average of twenty ormore times before it was all consumed. Actually, initially with thelubricant bowl full the liquid would not have been aerated at all, butas the reservoir was being emptied the liquid would have circulated manytimes.

This latter aeration in type B causes undesirable effects in manylubricating liquids. For example, with ordinary lubricating oils,aeration increases the rate at which the oil atomizes so that aerosoloutput may well increase percent or more as the liquid supply lessenswhich obviously is quite a factor, such as when a constant delivery ismost desirable or necessary for good lubrication. Aeration also causesoxidation which, in the case of compounded lubricants, may cause them tocompletely or at least partially lose their important characteristicsand thus operating specifications will not be met. Specifically,oxidation will usually destroy the functions of rustproofing liquids,de-oxidizers, deodorants and other like compounds and these defectsusually occur afterthe liquid has circulated only a few times and hasbecome well saturated with air. It should be mentioned that type B oflubricator does result in the fine micronic sized particles being trulyair borne, which is a definite advantage in that they will not drop outof the air stream as coarse particles do and they may be transportedproperly to the point of usage. At the point of application or usage ofsuch an aerosol for lubricating certain tools and other devices, ifnecessary, the aerosol may be passed through a reclassifier or condensedto form larger particles to increase wetting characteristics, all in amanner well known in the art.

It now has been determined that there are many usages, such as inconnection with high speed bearings, where the aerosol fed thereto forlubricating must be solely of the type including micronic or small,finely divided oil particles as unless the particles are maintained insuch condition when applied certain difiiculties will result, such as achatter of the bearings. Obviously type A falls short in this respect,but in many instances type B is satisfactory for this purpose, althoughthere are definite limitations, one being that the lubricator must beutilized in such a manner that it is undisturbed. By the latterexpression it is meant that the lubricator is not intended to be jostledabout or exposed to substantial amounts of movement caused by rapiddeceleration or acceleration or momentarily inverted from its normalupright position whereby it would not have the continual assistance ofgravitational forces to effect the separation of the coarse particlesfrom the usable aerosol. Many of these last named actions wouldobviously occur to lubricators incorporated in aircraft, missiles,rockets and 3 in many well known mechanical devices, such as jackhammers, where it is impossible during operations to be concerned withattitudes and inertial forces. For example, if type B lubricator weresuddenly turned over or even exposed to partial rotational movements,there would be slopping of the liquid lubricant and it would be hour,uniformly and constantly supplied by aerosol, is

necessary for successful operation or in other words lubricant must bedelivered uniformly and without fluctuation, even at extremely low flowrates. The second type of conventional lubricator cannot meet suchconditions as the supply of lubricant needed is too great,

due to the number of times aeration of the liquid takes place, asexplained, and furthermore the amount of mist delivered is not uniform,due to repeated aeration of the lubricant. Also there are instanceswhere the amount of liquid atomized must be constant, irrespective of'air pressure, and the prior types of devices are incapable of sofunctioning. There are conventional types of aerosol generators whichdeliver a flow of even 2 minims per hour in a series of widely spacedspurts (several minutes apart),'but such would result in the high speedbearing of the type mentioned burning out during the periods of nolubrication delivery. On the other hand, if the lubricant flow isincreased to the point where relatively constant delivery is obtained,the bearing overheats and burns out because of churning and friction ofthe excess lubricant.

Bearing the above in mind, the aerosol generator of the presentinvention overcomes the limitations of the prior art and conventionaltype lubricators discussed and results in creating directly an aerosolof finely divided micronic sized particles of liquid in air withoutcausing undesirable effects to the lubricant as the liquid upon beingdischarged into the air stream is completely broken up into micronicsized particles and at the same time the generators, illustratedhereinafter, result in a limited and uniform oil feed and are completelyindependent of any normal movements or attitudes. Specifically, theaerosol generator of this invention is unaffected in operation,regardless of any normal attitude to which it is exposed, it guaranteesa constant, uniform, nonfiuctuating and predictable supply of lubricantaerosol irrespective of the air pressure or velocity, it does notcontaminate or aerate the liquid supply prior to the atomizationthereof, and most important it creates directly and as the lubricant isdischarged into the air streama uniform aerosol of micronic sizedparticles of lubricant which are substantially 100 percent airborne andthus may be carried to the point of usage without settling out.

Thus it is an important object of this invention to provide an aerosolgenerator which creates directly and for all practical purposes nothingbut an aerosol of finely divided micronic sized particles of liquidlubricant in air.

Another object is to provide such an aerosol generator which may beoperated in any normal attitude and under any normal inertial force andwherein all of the liquid as it is discharged into the air stream isbroken up into a predictable supply of micronic size particles, such asthose measuring two microns or less.

A further object is to provide an aerosol generator which may beincorporated as an element in a lubricator and which overcomes theoutlined problems and difficulties of prior type lubricators.

Yet another object of this invention is to provide an aerosol generatorwherein the amount. of liquid atomized 4 is constant, irrespective ofthe pressure and velocity of the compressed air supplied to thegenerator.

The method of creating an aerosol as defined is another important objectof this invention.

Other objects and advantages of the invention will become apparent byreferring to the following detailed description in conjunction with thedrawings wherein several embodiments of the invention are illustrated,wherein like numerals and primes thereof represent similar elementsthroughout the figures and wherein:

Figure l is an enlarged cross sectional side elevational viewillustrating an aerosol generator of the invention in corporated inposition in an air conduit of an aerosol lubricator;

Figure 2 is an enlarged sectional view of the generator illustrated inFigure 1;

Figure 3 is a sectional view taken along the lines 3-3 of Figure 2; v

Figure 4 is an enlarged view taken along the lines 4-4 of Figure 2;

Figure 5 is an enlarged view partly in section similar .to that ofFigure3 but incorporating four generator tubes instead of two;

Figure 6 is an enlarged cross section of aportionof a typical bypasstype aerosol lubricator incorporating the principles of this invention;

Figure 7 is a sectional view taken along the lines 7--7 of Figure 6;.and

Figure 8 is a sectional view taken along the lines 8-8 of Figure 6.

Referring to the drawings in detail, it should be pointed out at theoutset for the sake of uniformity of language and a clear understandingof the invention that the expression aerosol or airline lubricatorrefers to the assembly including a body having air inlet and outletmeans, a lubricant bowl sealed to the body and the.generator of thisinvention, while the expression aerosol generator refers to structure ofthe type illustrated in Figure 2. Furthermore, the parts of thelubricator, other than the essential components of the generatorelement, may assume various forms and shapes. Thus it is to beunderstood that the partial lubricator structures illustrated in Figures1 and 6 are merely typical of various types that may be employed andmodified to include the aerosol generator of this invention. In thissame con nection, reference is made to C. A. Norgren et al. U.S. Patents2,718,934 and 2,661,814, Faust U.S. Patent 2,751,045 as well as manyother U.S. patents owned by the assignee of this invention asillustrating air line lubricator bodies in general which, as will beaparent, could easily be modified to include the teachings of thisinvention. For example, the generally vertical rotatable lubricantmetering assemblies or venturi plugs of the said patents would bereplaced by the instant aerosol generator. It will also be recalled thatmention was made that settling chambers were frequently needed prior tothe present development, and in this connection reference is made to thesettling chambers or spaces provided by the diffusion plugs 22 and 42 ofPatents 2,718,934 and 2,751,045.

Considering now the embodiment of Figures 1 to 4 inclusive, the trueinvention is depicted by the aerosol generator generally represented at1 as well as the method of generating a micronic size aerosol by the usethereof in combination with an air passage and lubricant supply and thecombined aerosol lubricator formed by incorporating the generator withthe lubricating bowl and air passage. Basically the generator utilizesseveral natural liquid phenomena including capillary attraction, wettingv cylindrical air conduit 4 having a threaded inlet 5 and a threadedoutlet 6 for respectively receiving in threaded engagement compressedair supply line 7 and aerosol discharge line 8. By means more completelyshown in some of said prior patents, such as, the clamp ring 11 inPatent No. 2,718,934, the under surface of body 3 is provided with anannular or peripheral gasket 9 for effecting a fluid seal between body 3and lubricator bowl 10, the latter containing a suitable supply oflubricant L.

As shown, bore or conduit 4 is actually stepped to provide annularshoulder means 11 and at substantially the longitudinal center of bore 4there is provided in body 3 a ring-like or annular groove 12. Atapproximately the bottom surface of body 3, as viewed in Figure 1, thereis provided a circular slot 13 communicating with groove 12 and withinwhich is supported, by any suitable means such as a friction fit, thetop end of a liquid oil supply tube 14 which thus communicates withgroove 12 and the lubricant within bowl 10. A fixed or adjustablerestriction of types well known in this art may be provided in tube 14to aid in control of the flow of liquid from bowl and as shown anadjustable restriction may take the form of a piece of ordinary felt 15constituting capil lary or wick means at the top end of tube 14.Capillary means 15 can be adjusted by compressing and modifying the tipend of tube 14 to provide a capillary bore would be an example of afixed restriction. Further, for a purpose that will be more fullydescribed hereinafter, there is provided liquid pressurizing means inthe form of orifice 16 communicating between bore 4 and the interior ofbowl 10.

The aerosol generator 1 is illustrated, due to the configuration of bore4, as comprising a round or cylindrical body 20, of brass for example,having front wall 21 and rear wall 22 and being of a diameter to bedetachably received in bore 4 with wall 22 abutting shoulder 11. Ofcourse, body may assume various shapes and it is desirable thatgenerator 1 be removable from bore 4, such as for cleaning purposes, andthus any suitable means such as a snap ring 23 engages the front wall 21to detachably hold the generator in the location illustrated inFigure 1. Substantially at the longitudinal center, body 20 is providedbetween walls 21 and 22 with an air jet inlet 24 of a size to pass thedesired amount of incoming compressed air, which in turn communicateswith an expansion chamber 25. At diametrically opposed points body 20 isprovided with acute angled bores 26 which extend from the exteriorperipheral surface 27 of body '20 to chamber 25. Positioned by anysuitable means (such as a friction fit) within each bore 26 andextending therefrom into chamber is a generator tube 28 also constructedof any suitable material such as brass. One end of each tube 28 is flushwith surface 27 and each of the diametrically opposed tubes is providedtherethrough with a capillary bore 29 generally not more than .015 inchin diameter.

The generator tubes 28 constitute an important part of this inventionand although such may assume various forms in body 20, Figures 1 to 4inclusive do illustrate a preferred arrangement of these tubes as aresult of experience and various tests. Measured from the axis of bore24, the preferred angle of each bore 26 and in turn tube 28 isapproximately 45 degrees, but such may easily vary from 30 to 60degrees. As is apparent, tubes 28 have portions 30 which extend withinchamber 25 and the tips of these portions are spaced from one another arather critical amount and this will be discussed hereinafter. Assumingthat the walls of tubes 28 intersect at a point adjacent inlet 24, thenit is preferable that this intersecting angle of the tubes be located adistance from inlet 24 equal to one and one-half to two times thediameter of jet inlet 24. At the inner end or tip of each portion 30 anarrow groove 32 parallel to the longitudinal axis of body 20 is milledso that each groove 32 has its longitudinal axis in axial alignment withair from inlet 24. As illustrated particularly in Figures 2 to 4, eachgroove 32 has sharp, square corners at the bottom there'- of, ispreferably about .010 inch wide (slightly less than the diameter of bore29) and a depth of about .008 inch. The last named depth is primarilyused if the jet inlet 24 is roughly of a size illustrated and for largersize jet inlet diameters the depth of each groove 32 would beproportionately increased, say to a maximum of .016 inch. At each sideof groove 32, the exterior surface of portion 30 is backed or milled offat preferably at 45 degree angle as illustrated at 33 to provide closeto knife-like edges 34. Such a structural arrangement results in aneedle-like point being formed at 35 at the tip of each generator tube.

It is to be understood that the scope of the invention is intended tocover an aerosol generator having one tube and more important one grooveor capillary surface 32 but, of course, Figures 2 and 3 illustrate apair of generator tubes 28 and such has been found very satisfactory.Also, additional tubes may be employed, such as the two pairs of equallyspaced and diametrically opposed tubes 28' illustrated in Figure 5. Inother words, one or various numbers of generator tubes may be used andfor extremely low flows it is preferable to utilize the structure ofFigure 3 but to block off one tube 28 whereby such will only be used asa dummy to balance air flow.

Hereinafter throughout the specification and claims there will beutilized the expression capillary surface and such has reference togroove 32. As is well known, a capillary bore or wick or even some drypowders would constitute particular types of capillary surfaces, thebore being open at both ends and generally formed from a cylindricalsurface of small radius of curvature. Groove 32 is likewise opened atboth ends and formed from a surface in channel form whose width iscomparable in size to the diameter of a capillary sized bore. Thus, theexpression capillary surface is meant to include structure thatfunctions to provide capillary attraction manifest in the phenomena ofsurface tension. Previous reference has been made to any attitude and bythis is meant any normal attitude or position generally anticipated in,for example, an airplane. Of course the present invention will beinstalled in an upright position as illustrated in Figure 1, but it maybe subjected to normal disturbances without affecting the operationthereof.

The essence of this invention resides in having the compressed airstream travel over a capillary surface which in the drawings is in theform of groove 3-2 as such results in the aerosol of air and, for allpractical purposes, percent finely divided micronic particles oflubricant. However, other designed capillary surfaces may be utilizedand are intended to come within the scope of this invention, althoughgroove 32 is preferred. As will be explained, it has been found thatneedle-like point 35 and knife-like edges 33 greatly aid in providingsuch an aerosol. To accomplish the feature of having a constant, uniformand predictable amount of atomization of liquid lubricant it isnecessary to have capillary means directly communicating with groove 32for feeding liquid lubricant to the latter. Although, for example, wickmeans could be utilized, the capillary means preferably takes the formof a capillary sized bore 29' of a diameter slightly larger than thewidth of groove 32-. In this same connection felt 15 is merely aconvenient means for causing lubricant to enter bore 29 and as a matterof fact a capillary sized bore could readily be substituted therefor.Further, it might be desirable to have wick means throughout tube 14 assuch would be advantageous in active attitudes to prevent any airpockets or the like forming in tube 14.

The embodiment of Figures 1 to 4 inclusive might well operate asfollows, assuming air under suitable initial supply tube 14 by virtue ofthe lower pressure existing in reduced section 25. It will be noted.that each bore 26 is substantially coextensive with groove 12 and assoon as the oil reaches groove '12, the liquid will then enter each ofthe capillary bores 29 and travel towards the tips of portions 3%. Oncethe liquid has started to enter each bore 29, such will continue to doso until the bore 29 has not only been filled but also each groove 32 isfilled to a meniscus. Thus, once primed, the filling of grooves 32' willoccur whether there is any pressure on the liquid L or not, this beingdue to the capillary action that takes place. Of course, other types ofliquid feeds may be employed but to have the flow at a truly steady .andconstant rate independent of air velocity, capillary or wick type feedmeans are necessary, as explained.

As the air pressure is increased, the velocity through jet tube 24increases and it starts to blow the oil off generator tubes 28 and whena pressure of about 3 p.s.i. is reached, the velocity is high enoughthat the liquid in grooves 32 will have been blown into a thin a fewmillionths of an inch thick. This film is then blown offthe trailingedges (the edges most adjacent wall 22) of grooves 32 and thereby all ofthe film is broken up into micronic sized and finely divided particlesof lubricant. Any larger particles or droplets that might ,collectbyrunning over the edges of grooves 32 run down thefaces 3 3 to theneedle-like points 35 where they are broken up into similar micronicsized particles. Thus all liquid discharged into the air stream isbroken up into micronic sized particles. As the liquid film is blownoffthe trailing edges of each groove, surface tension and wettingattraction keep feeding the liquid onto the capillary surfaces of thegrooves 32 and capillary attraction keeps the capillary tubes 29 filledup and supplying liquid to the capillary surfaces or grooves 32. Eachcapillary tube or bore 29 feeds the liquid very-uniformly, without anytendency for the contacting meniscus to cavitate where it is entering agroove 32 and thus cause a fluctuatingflow. Even under increased orvarying pressure and quite high fiow rates of compressed air the sameuniform delivery of micronic sized particles exists due to the capillarymeans 29 directly feeding each capillary surface 3-2. The molecularattraction and surface tension of the liquid film prevents it from beingblown oil the surface of the grooves 32 or being blown too thin orbroken. Tubes 28 are disposed in the jet air stream approximately asshown in the various views, as close to the center of the jet aspractical without touching, allowing a minimum of about .008 inchseparation. This configuration does not create any siphoning or venturieffect, maintaining, in effect, a neutral or balanced pressure at theexit of the capillary bores 29. This further allows prefect feeds ofliquid, unaffected by the velocity of air flow, resulting in moreprecise control of liquid output. Each groove 32 channels the air flowand reduces the agitation thereof, eliminating any tendency for theliquid meniscus at the end of bores 29 to cavitate. Of course theexpansion chamber 25 slows the travel of the air stream and aids inuniformity of travel of the aerosol. Repeating, the operation has beendescribed with reference to two generator tubes 28, but the operation ofan aerosol generator with one generator tube or four, as illustrated inFigure 5, should be apparent. In. actual operation, the principles ofthis invention have been utilized for uniformly and without interruptiondelivering lubricant flows as low as two-thirds minim per hour.

Considering Figures 6, 7 and 8, such has been illustrated merely topoint out one of the many modified uses of the principles of thisinvention and in this instance 'a pair of generator tubes are positionedin parallel spaced relationship. Patent 2,442,777 wherein there isillustrated an aerosol .lubricator of the bypass" type. Referring tothis patent, the incoming air flows through opening 32 and during:normal conditions the flap valve 29 would be closed, but

Reference is made to the C. A. Norgren when the pressure of the incoming.air is increased sufficiently the flap valve will be opened to providea bypass line and such an arrangement is often desirable to ac.commodate changes in required air volume and at the same time minimizeany change in air flow through 32. .In Figure 6 there is merelydisclosed a very small portion of the lubricator unit with numeral 40representing a section of the body casting and there being provided asuitable casting 41 forming with body 40 the air flow line .42 which iscomparable to the normal flow passage 32 of said last named patent.Between casting 41 and the bottom of housing 4am viewed in Figure 6,there is provided the flap valve 43- which would normally be closed andwhich would open upon suflicient air pressure being applied to bypassline 44. The top of casting 40 is provided with a'slot 45 and supportedtherein by any suitable means, such as the O-ring arrangement 46, is thegenerator unit 4-7 which is quite similar to generator 1 previouslydescribed. This unit47 includes a'circular body having a pair ofgenerator tubes 48 similar to tubes 27 arranged in parallel spacedrelationship instead of being diametrically opposed and each, of course,is provided .with portions 49 similar to portions 30 extending inexpansion chamber 50, the latter in turn communicating with outlet 51.Body 48 is likewise provided with a pair of passages 52 and 53comparable to previously described jet inlet 24 for directing theincoming air to tip portions 49 and of courseeach tube 48 has .acapillary sized bore 54 terminating in a capillary surface or groove 55similar to groove 32. The operation of the apparatus of Figures 6, 7 and8 including generator 47 should be apparent in .view of the detaileddescription in connection with Figure 2. The same type of aerosolincluding air and percent finely divided micronic oil particles isformed, this embodiment only being illustrated to show that the aerosolgenerator principle of this invention as well as the method of forming amicronic size aerosol by the use thereof may be incorporated in variouslubricators and furthermore the generator tubes may be arranged invarious patterns and, as mentioned, only one may be necessary in someinstances.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof and various changes in the size,shape and materials, as well as in the details of the illustratedembodiments, may be made .within the scope of the appended claimswithout departing from the spirit of the invention.

What is claimed is:

1. An aerosol generator comprising a body portion including'a passagefor the flow of compressed air therethrough with an inlet and outletcommunicating with the passage, a tubular member communicating at itsone end with a source of liquid and the opposite end thereof beingdisposed in the path offlow of the compressed air through the passage,the opposite end including a capillary sized groove, the groove beingaligned .with its longitudinal axis corresponding to the substantialdirection of air-flow through the passage whereupon the compressed airflowing across the grooved end is operative to break up the liquid intornicronic-sized particles for removal through the outlet.

2. An aerosol generator comprising a body portion including a passagewith inlet and outlet means for theflow a source of liquid, a passagedefiningan expansion chamher communicating with a restricted inlet and arelatively large outlet, a generally tubular member of capillarydimensions communicating at its one end with the source of liquid andits opposite end projecting into the path of flow of compressed airthrough the expansion chamber, the opposite end including a capillarysized grooved portion aligned with the direction of flow of compressedair through the passage, whereupon liquid delivered through said tubularmember into the groove portion is divided into minute particles by theflow of compressed air thereacross for delivery through the outlet.

4. An aerosol lubricator according to claim 3 wherein there is provideda pair of tubular members with the grooved portions on each positionedin diametrically opposed, spaced relationship in the expansion chamber.

5. In an aerosol generator having a source of liquid together with apassage for the flow of compressed air therethrough, a generator tube ofcapillary dimensions communicating at one end with the source of liquidand with the opposite end of said generator tube projecting into thepath of flow of compressed air through the passage, the opposite endincluding a grooved portion of capillary dimensions with thelongitudinal axis of the groove being directed in the substantialdirection of flow of compressed air through the passage.

6. In an aerosol generator adapted to receive a liquid lubricant andhaving a passage extending through the generator for the flow ofcompressed air therethrough, a generator tube defined by a bore ofcapillary dimensions including an inlet end communicating with thesource of liquid lubricant and an outlet end projecting into the path offlow of compressed air through the passage, the outlet end including agrooved portion of capillary dimensions and with the longitudinal axisof the groove disposed in the substantial direction of flow ofcompressed air through the passage, the side edges of the groovedportion terminating in knife-like edges and the trailing ends of thegrooved portion forming an acute angle with the longitudinal axis of thegroove.

7. In an aerosol generator adapted to receive a liquid lubricant andhaving a passage for the flow of compressed air therethrough, agenerator tube defined by a capillary bore disposed with its inlet endcommunicating with the source of liquid lubricant and with the outletend projecting into the path of flow of compressed air through thepassage, the outlet end terminating in an elongate groove aligned withits longitudinal axis in the substantial direction of flow through thepassage, the width of the groove being of a size less than that of thediameter of the capillary bore and with the sides of the grooveterminating in trailing ends of substantially needle-like size whereuponthe flow of compressed air through the passage is at a velocity suchthat liquid lubricant delivered into the groove is blown into a finefilm and broken up into finely divided micronic-sized particles fordelivery with the air through the passage.

8. In an aerosol generator comprising a source of liquid lubricant andhaving a passage including inlet and outlet means for the flow ofcompressed air therethrough, a plurality of generator tubes positionedin even, spaced relation into the passage, each generator tube beingdefined by a capillary bore projecting angularly into the passage in thedirection of flow of the compressed fluid, each bore including an inletend communicating with the source of liquid lubricant in the generatorand an outlet end which is tapered for alignment in parallel relationwith the longitudinal axis of the passage, the outlet end of each boreincluding a grooved portion extending thereacross in communication withthe bore with its longitudinal axis disposed to correspond with thedirection of flow of compressed air through the passage, each groovedportion having a width less than the diameter of the respectivecapillary bore and with the sides of the groove terminating inknife-like edges and the trailing, downstream ends of each grooveterminating in needle-like points whereupon the flow of compressed airacross the capillary groove surfaces will cause liquid lubricantdelivered onto the groove surfaces to be blown into a fine film anddivided into micronic-sized particles at the trailing ends thereof fordelivery in the form of a fine mist with the compressed air through theoutlet end of the passage.

References Cited in the file of this patent UNITED STATES PATENTS883,374 Akeson Mar. 31, 1908 963,985 Best July 12, 1910 1,112,025 NelsonSept. 29, 1914 1,204,309 Peterson Nov. 7, 1916 2,353,865 Armstrong July18, 1944 2,439,910 Snyder Apr. 20, 1958 2,826,400 Sterner et a1. Mar.11, 1958 2,889,009 Endebak et al. June 2, 1959 2,906,463 Curry Sept. 29,1959 FOREIGN PATENTS 890,830 France Feb. 18, 1944

